PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value  

Re: PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value

Hey guys,

Further to this, i reconfigured the fan such that its maximum speed was 70% (in slic3r) and managed to keep the nozzle temp above 190 but only just. Set point for the PLA i am using is 230 DegC, when the cooling fan kicks in after the first layer the temp drops to 193 DegC (with fan max at 70%). The current print is five hours in and the nozzle temp has managed to rise to just over 200DegC

Any assistance would be great.

Thanks

Angus

Re: PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value

Hi Angus.

For PLA just change the fan speed in Slic3r after 1st layer to 50% and everything will work again. Tested 😉

Re: PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value

Hi Angus

I don't yet have a Prusa I3 (currently running a clone) but here are my thoughts:

Ensure that the fan is directing air to the printed part and not the heater block
Ensure that the heater is firmly fixed into the block
Ensure that the thermistor is fully inserted into the block
Ensure the wiring to the heater is OK - remove and reinsert the plugs/wires, ensuring that any screw terminals capture the wire and not the insulation.

There is also the possibility of a "dry joint" - a bad solder connection on the board itself - where the connector is soldered to the board.

If the above are OK, then I would suspect the heater itself, as this simply should not happen. As I said, I don't have the Prusa. Is there a LED on the board which indicated when the heater is on? If so, is this LED lit all the time when the fan is on? (If there is no LED, then you could place a meter across the heater outputs on the board. A meter could indicate whether full voltage is being applied and could point to where the problem may lie.

In any event and as this forum doesn't appear to be regularly monitored by PR, if you can't fix this I would suggest that you contact their support department via email.

This printer should be able to print ABS with the cooling fan running; the temperatures you are getting are way too low.

Peter

Re: PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value

Maybe increasing fan speed continuously should do the trick. But it requires some manual gcode tweaking. Search for a line with M106 and M107 commands when there is M106 S255, change it to M106 S127 somewhere later raise the S parameter and finish up to S255 - full speed. This may give some time for heater to compensate temperature drop.

Re: PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value

Petr

Sorry I disagree

The last thing anyone (especially someone new to 3D printing) wants to do is to mess around with gcode.

Angus is printing with PLA; the nozzle temperature is dropping too low to print, therefore there has to be a problem here which requires fixing. Just once; not with every print.

Either the thermistor is not reporting temperatures correctly or the heater is not supplying sufficient heat. This must be rectified. Angus may want to print ABS in the future; he will not be able to do so with things as they are at present.

Peter

Re: PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value

Hey Guys,

Thanks for the feedback. I certainly don't want to be mucking with the G-Code.

I will check things out as suggested in the replies and let you know, work is pretty intense at the moment so will take me a couple days.

I am hoping that someone from PR will reply, I didn't want to purchase a printer which I had to much around with to get working, I wanted a fully supported printer which just works. Everything should be stock as supplied, when you buy the printer it comes with the hot end already assembled and the thermistor installed, likewise with the fan mount, that is stock as supplied and installed as per the manuals (best I can tell). I really dont want to be muching around with G-Code or the firmware, that is not what I payed the money for so hopefully this is something which I have done wrong and we can fix it.

Will try things and let you know, in the meantime I hope someone from PR chimes in with some further assistance. I assume it is a problem on my end as would expect there be other comments if this a systemic issue. At the moment I wish I hadn't payed the money to upgrade and just kept with the 3mm extruder. It was working without any hassles.

Thanks again,

Angus

Re: PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value

Hi Angus

One more thought... Is le printer located where there is a cool draught? If so, it will need protecting.

I still favour the possibility of a high resistance joint/connection on the Rambo. If you have a multimeter, can you measure the resistance of the heater from the solder connections underneath the connector on the Rambo?

You can find the specified resitances here: http://wiki.e3d-online.com/wiki/E3D-Lite6_Assembly - the "Heater Cartridge" section

If you measure as suggested than this will also include and high resistance connections and maybe give a clue as to what is going on.

Peter

Re: PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value

Thanks for the reply again,

I have checked a few things,

"Ensure that the fan is directing air to the printed part and not the heater block". This is as per installation instructions, best I can tell the air is being directed as per Prusa design. There is not much I can do about this besides designing a new part.

"Ensure that the heater is firmly fixed into the block". Appears to be fixed firmly. I cant move it on the block

"Ensure that the thermistor is fully inserted into the block". Thermistor comes pre installed, I haven't removed it yet, however, it appears to be inserted correctly.

"Ensure the wiring to the heater is OK - remove and reinsert the plugs/wires, ensuring that any screw terminals capture the wire and not the insulation." Will do this in the coming days as well as check the resistance as per you note.

There is definitely something going on, I tried printing some Colorfabb XT tonight with the settings provided by Prusa and even then the nozzle temp could not be sustained. They set the extruder temp at 240 DegC with the cooling fan set at min 30% and max 50%, even then the nozzle temp dropped to around 230DegC for the print. That puts it below the recommended printing temp for that material which is useless.

Very frustrated at the moment, will try some other things and get back in touch.

Angus

Re: PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value

Angus

The more I read about your problem, the more I am convinced it is a connector issue - a "high resistance" joint somewhere.

Others have also noted this issue, which has resulted in some melted plastic connectors.

When I received my Chinese printer, that had a dry joint under the E-Motor connector, so the motor sometimes worked and sometimes did not. Now I know the quality of my Melzi clone board is not brilliant, but these things can happen occasionally, especially with the lead-free solder in use nowadays.

Peter

Re: PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value

Argus, I have the same problem (and I am not alone). So far I didnt found the problem and onsly solution for now is lower print fan for around 50%. I think there is definitelly something wrong with heater/rambo/power supply. No answers from support for 1-2 months, sadly it looks like they dont care about this forum anymore.

I recently bought new heater and I will test it, but old heater have proper resistance. My guess for now is some rambo issue. Maybe I will try to solder heater wires directly to board.

Re: PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value

Roman/Angus

Just another thought; if this is a power problem can you please try printing without the bed heater turned on? If the nozzle temperature is stable without the bed heater drawing power, then this could point to insufficient power being available to run both heaters.

Peter

Re: PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value

It is no difference without bed heating, but when I pause printing (heater and fans still running) or slow it for like 30-40%, temperature start to raise slowly.
When I do preheat for 210C/50C and turn on print fan to 100% manually = temperature about 206C (nozzle is close to bed)
Same settings while printer is printing = temperature about 189C.

There is separate power circuit for heatbed from power supply and even in RAMBo board so it may not be so relevant for nozzle cooling problem :o/.

Re: PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value

OK, so I think there is an issue with the lite6 hot end...

I had a look; the cut-away drawing shows the PTFE tube going right down to the nozzle - in fact, inside the heater block.

PTFE melts at 327 degrees, but becomes soft well before that. Hence e3d's absolute maximum temperature of 245 degrees (although Josef did state elsewhere that it works above this temp, I am inclined to agree with the manufacturer...)

E3d also specify a maximum printing speed for this hot-end of 50mm/sec. That of course is a quite useless value, unless you know the width and layer height - ie we need to know the maximum volume it can melt every second.

However, the standard hot-end from E3d can print up to 100mm/sec; therefore the lite version must run at only 50% of the speed that a reasonable hot-end can print at.

Can I suggest that you try printing at lower speeds? Try half your normal print speed to start with to see how that goes.

Personally, after reading up on the lite6 hot-end, I think this is a very bad choice by PR. Cutting costs in this area is never a good thing.

There is good news in that E3D do state that their hot ends are interchangeable, so it should be possible to swap the lite6 out for a decent V6,

Peter

Re: PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value

Yes, but why majority of owners dont have this problem? Thats bothering me. I will try new heater today or tomorrow.

Printing speed propably isnt problem. My max speed is 40mm/s and same problems are even with 20-25mm/s.

PR stated, that Lite6 was chosen because of its durability.

Re: PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value

Thanks peter,

I have tried multiple speeds and doesn't make a difference, everything works fine until the fan comes on and then everything goes pear shape from there. I agree with you though about the cost cutting, I personally feel a bit duded, I only found out it was the lite version by reading a post on here. I couldn't see it anywhere else which is really something they should advertise. Some of the filaments I want to use require temperatures above the maximum for the hot end so I now have to spend even more money to get the thing printing what I want. I must have missed all these important limitation details in their advertising and documentation.

Also seems the 1.75mm version was a bit rushed, the 3mm version that I originally bought was excellent, things only started going downhill when I upgraded. I am still happy to accept that I have done something wrong and there is a fix for the issues but the longer PR stay silent on this the more I think they know there is an issue and can't comment because they don't have a fix yet.

Angus

Re: PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value

Angus

I am becoming more frustrated with the support side of this company every day.

They are great at responding when you want to buy something. but apparently very poor when there is a problem.

For me, the worst thing is that these problems should not happen; I think PR don't have answers. My cheap Chinese printer has been working constantly for many months (after initial teething problems) , with only basic servicing. It's design is fairly basic as well. The hot end is very cheap - but it works.

I have added a cooling fan blowing onto the barrel, but this really isn't needed as the PTFE tubing stops well short of the heater block.

Currently I am printing the Saturn V (from NASA); it is 3 feet tall already with 2 more stages to print. Printing PLA @ 205 degrees, the temperature varies only ± 0.6 degrees. The printer is also sitting in a draft and the board fan is also moving air over the extruder.

I will have my Prusa printing tomorrow; will let you know how that performs. I have ABS and HIPS to test with. I hope I don't have to push up the temperature over 240 degrees...

Peter

Re: PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value

Hello,
I'm very sorry to hear this kind of issue, we're still working on this one and doing our best to avoid this happening.
Please contact our support through live chat or e-mail, add a link to this post and we'll send you new hot end.
If you can send your faulty hot end to us after receiving the new one, send receipt to your support team and the'll give you coupon matching your shipping price.

Sorry for the inconvenience, we'll inform you here about this situation after we'll receive your faulty hotends.

SOLVED! Re: PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value

I just solved the problem, it was faulty heater :-). I just replaced heater and problem is completely GONE, temperature is not droping anymore :geek: .

Replacement is 30W heater from eBay. Faulty E3D heater should be 25W according to their site, but there is "E3D 12V 30W" sign on it :-).

I am so happy I finally solved it.

http://www.ebay.com/itm/200960486294

Re: PLA Cooling fan drops nozzle temp below EXTRUDE_MINTEMP value

Hi Roman

That's great news, well done!

Did you measure the old heater resistance? Can you please let me know if you did. SHould be around 6 Ohm, but then again, the cold measurement may be OK and it may only have an issue when hot.

I put my printer together last evening. The temps seem stable at 230 with both fans running, but I will probably invest in a V6 as the lite won't allyw me to print quickly enough - I do a lot of very long prints (24+ hours) and I need to get them out as quick as possible, so 0.25mm layers etc.

Peter